<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .box {
      width: 200px;
      height: 200px;
      background-color: rgb(187, 150, 156);
    }
  </style>
</head>

<body>
  <!-- 
    :style="{css属性名1: css属性值, css属性名2: css属性值, ...}"
    适用于某个具体属性的动态设置
   -->
  <div id="app">
    <div class="box" :style="{width, height, backgroundColor}"></div>
  </div>
  <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        width: '400px',
        height: '400px',
        backgroundColor: 'green'
      }
    })
  </script>
</body>

</html>